The numbers 1310 and 1550 refer to the wavelength of light used in the optical transmitters of SFP (Small Form-factor Pluggable) modules. These wavelengths are commonly associated with fiber-optic communication. Here are the key differences between 1310nm and 1550nm SFP modules: 

1. Wavelength:

• 1310nm: SFP modules with a wavelength of 1310nm are often used for short to medium-distance transmissions. They are suitable for multimode fiber and some types of single-mode fiber. The 1310nm wavelength is often employed in applications like local area networks (LANs).

• 1550nm: SFP modules with a wavelength of 1550nm are typically used for longer-distance transmissions over single-mode fiber. This wavelength is less susceptible to signal attenuation in long-distance transmissions and is commonly used in metropolitan area networks (MANs) and long-haul communications.

2. Distance and Attenuation:

• 1310nm: SFP modules operating at 1310nm are generally associated with shorter transmission distances. They may experience more signal attenuation over longer distances compared to 1550nm.

• 1550nm: SFP modules operating at 1550nm are designed for longer-distance transmissions due to lower signal attenuation at this wavelength in single-mode fiber.

3. Applications:

• 1310nm: Commonly used for short to medium-distance connections, such as within a data center or between buildings in a campus network. Suitable for multimode and some single-mode applications.

• 1550nm: Ideal for longer-distance connections, such as interconnecting data centers in different locations or for long-haul telecommunications.

4. Dispersion:

• 1310nm: Generally exhibits lower chromatic dispersion compared to 1550nm, which is beneficial for certain types of fiber-optic communication.

• 1550nm: May experience higher chromatic dispersion, but this can be compensated for with dispersion compensation techniques.

When selecting between 1310nm and 1550nm SFP modules, it's essential to consider the specific requirements of the network, including the transmission distance, the type of fiber used, and the overall network architecture.